The two Ivy League-trained economists have emerged as leading contenders to replace Ben Bernanke as chairman of the Fed, the nation’s central bank. Obama could announce his nominee in the coming weeks.

As presidential nominations go, the top Fed post ranks higher than Cabinet secretaries without the longevity of Supreme Court justices. Fed chairmen serve four-year terms but their stints don’t coincide with presidential terms and the Fed’s independence is jealously guarded.

The central bank wields extraordinary influence over the lives of millions of Americans. Its two main missions are fostering maximum employment and stabilizing prices. With its power to regulate the supply of money and set interest rates, it influences economic activity, hiring and inflation. It also is the leading regulator of banks and plays a crucial role as the country’s lender of last resort when banks can’t get their money elsewhere.

So in the aftermath of a calamitous financial crisis in 2008 and with national unemployment still high at 7.4 percent, the selection of a successor to Bernanke has assumed all the drama of a high-stakes Washington moment.

A look at Summers and Yellen and their experience and stand on some issues:

EXPERIENCE

Summers has held numerous public policy posts, beginning as a member of the Council of Economic Advisers under President Ronald Reagan in 1982. But he has not worked inside the Fed. He was chief economist at the World Bank from 1991 to 1993. Under President Bill Clinton, Summers served as deputy secretary and then secretary of the Treasury. He was president of Harvard University from 2001 to 2006. Obama appointed him to serve as the director of the National Economic Council in 2009, a post he held until November 2010. He is a professor of economics at Harvard. He also has ties to Wall Street, having consulted for Citigroup and the exchange company Nasdaq OMX.

Early in her career, Yellen worked as an economist at the Fed and was a business and economics professor at the University of California, Berkeley, when she became a member of the Fed’s board of governors in 1994. Clinton selected her to chair his Council of Economic Advisers from 1997 to 1999. She was president of the San Francisco Federal Reserve Bank, one of 12 Federal Reserve districts. In 2010, Obama selected her as vice chair of the Fed’s board of governors, a position she has held since.

REGULATION

Summers helped the Obama administration devise the proposals that eventually would shape the financial regulation bill that Congress passed and Obama signed into law in 2010, much of it over the objections of big banks. That aggressive stance is in contrast to Summers’ support for legislation during the Clinton administration that allowed commercial banks to engage in investment banking, a deregulatory step that permitted banks to buy and sell of mortgage backed securities and other financial instruments that increased their exposure to risk. Summers’ critics say his Wall Street work and his stance in the 1990s suggest he would be a less than enthusiastic regulator. But his backers say his support for a regulatory overhaul after the financial crisis belies those concerns.

Yellen has advocated tough regulations since her time at the San Francisco Fed. She is credited for issuing early warnings that the housing bubble and unregulated financial practices threatened the economy. As the Fed’s vice chair she has called for additional financial system safeguards. In a speech in June she said it might be necessary to require banks to set aside more capital than the increases that have been proposed to reduce the threat they might pose to the broader financial system. Some lawmakers have called for a return to pre-Great Depression restrictions separating commercial banks from investment banks. “I am not persuaded that such blunt approaches would be the most efficient ways to address the too-big-to-fail problem,” she told an international monetary conference in Shanghai, China.